scholarly journals THE INFLUENCE OF BORON CARBIDE ADDITIVE ON THE STRUCTURE AND HARDNESS OF A NICKEL-BASED COATING

2021 ◽  
pp. 89-97
Author(s):  
U. S. Starikova ◽  
◽  
N. N. Soboleva ◽  
A. V. Makarov ◽  
E. V. Kharanzhevsky ◽  
...  
Keyword(s):  
Boron Carbide ◽  
Laser Cladding ◽  
High Hardness ◽  
Industrial Applications ◽  
Grain Structure ◽  
Heating And Cooling ◽  
Fine Grain ◽  
Microscopic Studies ◽  
Nicrbsi Coating ◽  
Fine Grained Structure

Laser cladding is increasingly frequently used in various branches of mechanical engineering since it has such advantages over traditional methods of depositing coatings as high heating and cooling rates and minimal mixing of base and melting materials. Laser-clad coatings are usually characterized by a fine-grained structure and a minimal heat-affected zone. Coatings formed from the Ni–Cr–B–Si powders are also very common in industrial applications, as they have good resistance to wear, corrosion, erosion, etc. Various strengthening particles can be added to this group of powders to improve the properties of the deposited coating. Boron carbides can act as such particles since they have high hardness, thermodynamic stability, and wear resistance. In this regard, the paper investigated the influence of the 7 wt. % of boron carbide B4C addition on the structure and hardness of the NiCrBSi coating formed by laser cladding of PG-SR2 powder on the surface of 30HRA steel. Using the scanning electron microscope, the authors carried out microscopic studies of the structure of NiCrBSi and NiCrBSi–B4C coatings and presented the results of X-ray spectral microanalysis. The study shows that the structures of both coatings in the deposited state are characterized by uniformity and fine-grain structure. The investigation revealed that the samples with NiCrBSi and NiCrBSi–B4C coatings have a narrow transition zone from the deposit to the base metal. The paper presents the results of measuring the microhardness of coatings indicating a decrease in the microhardness of laser-clad nickel-based coatings with the boron carbide addition.

Grain Structure and Precipitates in Squeeze Casting Al-Li-Mg-Zr Alloy

2014 ◽  
Vol 887-888 ◽  
pp. 329-332
Author(s):  
Li Fan ◽  
Zhong Wei Chen ◽  
Qi Tang Hao
Keyword(s):  
Grain Boundaries ◽  
Squeeze Casting ◽  
Grain Structure ◽  
Fine Grained ◽  
Fine Grain ◽  
The Matrix ◽  
Fine Grained Structure ◽  
Heat Treated Condition ◽  
Micrometer Size ◽  
Zr Alloy

Grain structure and precipitates in squeeze casting Al-Li-Mg-Zr alloy for aircraft industry were investigated in heat treated condition, using X-ray diffraction, optical microscopy and transmission electron microscopy. An ultra fine grained structure in sub-micrometer size was obtained, having fine nanograins in it with polycrystalline diffraction rings that are different from the single-crystal patterns in the matrix. Ultra fine grain areas are generally located on the grain boundaries and sub-grain boundaries. In addition, TEM observations indicates the presence of lenticular δ' (Al3Li) phases that symmetrical distributed around the GP zones. The alloy also contains spherical β' (Al3Zr) dispersoids, and S1 (Al2MgLi) phases.

Grain Refinement of 6061 Al Alloy by the Modified Strain-Induced Melt- Activated(SIMA) Process for Semi-Solid Processing

2007 ◽  
Vol 119 ◽  
pp. 311-314 ◽  
Author(s):  
Young Buem Song ◽  
Chun Pyo Hong
Keyword(s):  
Grain Refinement ◽  
Grain Structure ◽  
Al Alloy ◽  
Fine Grained ◽  
Fine Grain ◽  
Fine Grained Structure ◽  
Size Uniformity ◽  
Sima Process ◽  
Semi Solid ◽  
6061 Al Alloy

The dynamic process of fine grain evolution of 6061 aluminum alloy during modified strain-induced, melt-activated (SIMA) process was studied. The modified SIMA process employed casting, two stage homogenization, warm multi-forging, and recrystallization and partial melting (RAP). Multi-forging was carried out at a strain rate of 9x10-3 s-1 to accumulate high strains, with decreasing temperature from 250 to 200 °C. The alloy multi-forged with the accumulated strain of about 12 and RAP at 640 °C for 10 min exhibited the uniform equiaxed recrystallized grain structure. Accordingly, it was evident that multi-forging was very effective on grain refinement and grain size uniformity. The present modified SIMA process was discussed as an alternative thermo-mechanical processing for preparing the alloys with fine grained structure for semi solid processing.

Microstructure Development in a High Current Density NbTi Superconducting Composite

1985 ◽  
Vol 43 ◽  
pp. 186-189
Author(s):  
P. J. Lee ◽  
D. C. Larbalestier
Keyword(s):  
Current Density ◽  
High Current Density ◽  
Cold Drawing ◽  
Heat Treatments ◽  
Grain Structure ◽  
Fine Grain ◽  
Boundary Film ◽  
Quantitative Basis ◽  
Cold Worked ◽  
Very High

Several features of the metallurgy of superconducting composites of Nb-Ti in a Cu matrix are of interest. The cold drawing strains are generally of order 8-10, producing a very fine grain structure of diameter 30-50 nm. Heat treatments of as little as 3 hours at 300 C (∼ 0.27 TM) produce a thin (1-3 nm) Ti-rich grain boundary film, the precipitate later growing out at triple points to 50-100 nm dia. Further plastic deformation of these larger a-Ti precipitates by strains of 3-4 produces an elongated ribbon morphology (of order 3 x 50 nm in transverse section) and it is the thickness and separation of these precipitates which are believed to control the superconducting properties. The present paper describes initial attempts to put our understanding of the metallurgy of these heavily cold-worked composites on a quantitative basis. The composite studied was fabricated in our own laboratory, using six intermediate heat treatments. This process enabled very high critical current density (Jc) values to be obtained. Samples were cut from the composite at many processing stages and a report of the structure of a number of these samples is made here.

CONTINUOUS-CAST 45-12 DUCTILE IRON

Alloy Digest ◽  
1989 ◽  
Vol 38 (4) ◽  
Keyword(s):  
Continuous Casting ◽  
Ductile Iron ◽  
Heat Treating ◽  
Grain Structure ◽  
Continuous Cast ◽  
Good Surface ◽  
Fine Grain ◽  
High Speeds ◽  
Good Surface Finish ◽  
Iron Grade

Abstract Ductile Iron grade 45-12 produced by continuous casting has consistent density and fine grain structure. It is the softest of the regular grades of ductile iron and it machines at high speeds with good surface finish. This datasheet provides information on composition, physical properties, microstructure, hardness, elasticity, and tensile properties. It also includes information on heat treating, machining, and joining. Filing Code: CI-58. Producer or source: Federal Bronze Products Inc..

KETOS

Alloy Digest ◽  
1960 ◽  
Vol 9 (8) ◽  
Keyword(s):  
Physical Properties ◽  
Tensile Properties ◽  
Tool Steel ◽  
Heat Treating ◽  
Grain Structure ◽  
Steel Company ◽  
Fine Grain ◽  
Crucible Steel

Abstract KETOS is an oil-hardening non-deforming tool steel having deep hardening qualities with a fine grain structure. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as deformation. It also includes information on forming, heat treating, and machining. Filing Code: TS-96. Producer or source: Crucible Steel Company of America.

Ionic Conductivities of Doped CeO2 Thin Films as Related to Their Microstructure

1995 ◽  
Vol 411 ◽  
Author(s):  
Chunyan Tian ◽  
Siu-Wai Chan
Keyword(s):  
Thin Films ◽  
Electrical Properties ◽  
Ionic Conductivities ◽  
Dielectric Constants ◽  
Grain Structure ◽  
X Ray Diffraction ◽  
Fine Grain ◽  
Brick Layer Model ◽  
Columnar Grain ◽  
Beam Deposition

ABSTRACTThin films of 4% Y2O3 doped CeO2/Pd film/(001)LaA103 with a very low pinhole density were successfully prepared using electron-beam deposition technique. The microstructure of the films was characterized by x-ray diffraction and the electrical properties were studied as a function of temperature with AC impedance spectroscopy. A brick layer model was adopted to correlate the electrical properties to the microstructure of the films, which can be simplified as either a series or a parallel equivalent circuit associated with either a fine grain or a columnar grain structure, respectively. The conductivities of the films fell between the conductivities derived from the two circuit models, suggesting that the films are of a mixed fine grain and columnar grain structure. The measured dielectric constants of the films were found smaller than that of the bulk.

Magnetic properties of MnZn ferrite with ultra-fine grain structure

2003 ◽  
Vol 254-255 ◽  
pp. 538-540 ◽  
Author(s):  
J Moulin ◽  
Y Champion ◽  
J.M Grenèche ◽  
F Mazaleyrat
Keyword(s):  
Magnetic Properties ◽  
Grain Structure ◽  
Mnzn Ferrite ◽  
Fine Grain

The Possibility of Manufacturing Long-Length Metal Products with Ultra-Fine Grain Structure by Combination of Strain Effects

2016 ◽  
Vol 685 ◽  
pp. 487-491 ◽  
Author(s):  
Mikhail Chukin ◽  
Marina Polyakova ◽  
Alexandr Gulin ◽  
Olga Nikitenko
Keyword(s):  
Steel Wire ◽  
Continuous Method ◽  
Grain Structure ◽  
Strain Effect ◽  
Strain Effects ◽  
Fine Grain ◽  
Wide Range ◽  
Processing Modes ◽  
Efficiency Estimation ◽  
Metal Products

It is shown that combination of strain effects leads to possessing the ultra-fine grain structure in carbon wire. The continuous method of wire deformation nanostructuring was developed on the basis of simultaneous applying of tension deformation by drawing, bending deformation when going through the system of rolls and torsional deformation on a continuously moving wire. One of the main advantages of the developed method is that various hardware devices and tools already applied for steel wire production can be used to implement this method thus simplifying its introduction to the current industrial equipment. The efficiency estimation of the developed continuous method of deformation nanostructuring was carried out using carbon wire with different carbon content. It is shown that the mechanical properties of the wire after combination of different kinds of strain can vary over a wide range. This method makes it possible to choose such modes of strain effect, which can provide the necessary combination of strength and ductile properties of carbon wire depending on its further processing modes and application.

Microstructural Changes of Welded Zn-AI Alloy

1994 ◽  
Vol 367 ◽  
Author(s):  
Yao Hua Zhu
Keyword(s):  
Phase Transformation ◽  
Early Stage ◽  
Dendritic Structure ◽  
Metastable Phases ◽  
Grain Structure ◽  
Al Alloy ◽  
Cast State ◽  
Microstructural Changes ◽  
Fine Grain ◽  
Ageing Processes

AbstractExtruded eutectoid Zn-Al alloy was welded by a melt of the same eutectoid alloy. Two different microstructures were observed in the joint part and the bulk of the welded alloy. Typical dendritic structure of as cast Zn-Al alloy was observed in the joint part of the welded alloy. The bulk ofthe welded Zn-Al alloy appeared as fine grain structure. Two different metastable phases η'T decomposed from η's of chilled as cast state and η'E of extruded state were found to be unstable during early stage of ageing. A four phase transformation occurred after the decompositions of these two metastable phases of η'T. Microstructures of both joint part and bulk of the welded alloy were investigated parallely during ageing processes.

Role of grain boundaries in the epitaxial realignment of undoped and As-doped polycrystalline silicon films

1993 ◽  
Vol 8 (10) ◽  
pp. 2608-2612 ◽  
Author(s):  
C. Spinella ◽  
F. Benyaïch ◽  
A. Cacciato ◽  
E. Rimini ◽  
G. Fallico ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Grain Structure ◽  
Native Oxide ◽  
Thermally Induced ◽  
Si Substrates ◽  
As Doping ◽  
Fine Grain ◽  
Si Films ◽  
Polycrystalline Silicon Films ◽  
Reduced Density

The early stages of the thermally induced epitaxial realignment of undoped and As-doped polycrystalline Si films deposited onto crystalline Si substrates were monitored by transmission electron microscopy. Under the effect of the heat treatment, the native oxide film at the poly-Si/c-Si interface begins to agglomerate into spherical beads. The grain boundary terminations at the interface are the preferred sites for the triggering of the realignment transformation which starts by the formation of epitaxial protuberances at these sites. This feature, in conjunction with the microstructure of the films during the first instants of the heat treatment, explains the occurrence of two different realignment modes. In undoped films the epitaxial protuberances, due to the fine grain structure, are closely distributed and grow together forming a rough interface moving toward the film's surface. For As-doped films, the larger grain size leaves a reduced density of realignment sites. Due to As doping some of these sites grow fast and form epitaxial columns that further grow laterally at the expense of the surrounding polycrystalline grains.

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